Hey, Gary, there is nothing worse than losing the fish of a lifetime to a knot failure, so it’s always important to consider a knot’s true strength before selecting it as your go-to knot. And, the knots can be finicky from line to line, since the lines are are all just a hair different in their quality. Improved clinch and Davy (similar to Orvis knot) knots are ones I use the most, keeping in mind they are fast knots to tie. Of course, there are others out there that I am sure are preferred, but these work for me. Some of the Colorado guides I know rely on the Davy knot for use and judging by the monster trout they bring in, no doubt works. For mono to fluorocarbon, like leader to tippet or leader(mono) to butt(mono), I use a blood knot. With fluoro, it is important to slowly seat the knot to avoid friction heat. Like with the Improved Clinch, you might experiment with the number of wraps to get the best fit
regards,
pat